1. Field of the Invention
The present invention relates generally to pumps and monitoring systems, and more specifically to hydraulically operated pumps for in-ground filtration and monitoring of wells and for sampling other fluids.
2. Discussion of Background
Public concern about the environment and various government-imposed environmental regulations have resulted in an increase in requirements relating to the monitoring of ground water quality. In response to these requirements, water quality analytical capabilities have been improved and water sampling equipment has been developed. However, much of the previously developed sampling equipment has not been effective in obtaining consistent, non-contaminated water samples that accurately represent the water system that is being monitored.
Sampling pumps have been used for years to intermittently withdraw fluid samples from pipes, wells, and other sources, and then inject those samples into suitable containers for subsequent analysis. The inadequacies of previous sampling equipment stem largely from such causes as cross-contamination between sampling sites, ineffective and inconsistent field cleaning methods, contamination due to equipment handling, inconsistent well samples, and inadequate on-site or in-situ measuring techniques. In addition to the present sampling quality problems, much of the previous equipment has been bulky and heavy, and thus difficult to transport from one monitoring site to another. Finally, much of the previous equipment has proved to be complicated to operate, inordinately expensive, and impractical for sampling at remote locations where site access is severely limited.
There are many examples of devices for collecting or facilitating the collection of samples of fluid streams from various environments. Several of the devices have the capability to reach out from the main pump or collection body for withdrawing a fluid sample from a source. For example, see Welker, in U.S. Pat. No. 4,628,750 and Jaeger, in U.S. Pat. No. 4,475,410, in which the main pump or collection body is external to the fluid stream process lines.
Dickinson, et al., in U.S. Pat. No. 4,489,779, disclose a device for withdrawing fluid samples from ground water wells. The device uses a fluid activated pump to draw in a sample fluid through the inlet port and to control movement of the sample fluid through the outlet port, which is preferably connected to a sample collection vessel. Dickinson, et al. show the pump within a well casing, and thus suggest at least partial in-situ sample collection.
Peterson, in U.S. Pat. No. 3,200,649, discloses a device for collecting a sample from a sewer conduit. The device uses air power to actuate a pair of piston members or plungers to move the sample fluid through the system and into a collection chamber.
There remains a need for a complete in-situ pump and monitoring system for in-ground well sampling and for other small diameter pipe systems that is compact and small enough to be placed within the fluid process streams or pipes, that provides a continuous and accurate method for monitoring a fluid or fluid sample, and that is part of the pump.